A high-calcium fly ash was studied as mineral addition in mortar mixture. It is replaced with the Portland cement on mass basis at replacement ratios of 0%, 10%, 20%, 30% and 40%. The sand-binder material ratio and water-binder material ratio were 2.75 and 0.485 for all mixtures, respectively. The influence of high-calcium fly ash (HCFA) on compressive strength, flexural strength, porosity, water absorption, drying shrinkage, abrasion resistance and freeze/thaw resistance were investigated. The laboratory results showed that 10% fly ash replacement improved the properties of mortar mixture, and 20% fly ash replacement developed almost the same properties compared to reference Portland cement mortar. It is concluded that replacement of fly ash with cement up to 20% is seemed to be possible for current fly ash without significantly affecting the properties of mortars. Due to its low shrinkage development, the use of 30% fly ash may be possible; however, it caused little decrease in mortar performance. The use of 40% fly ash in mortar was not recommended, since it caused swelling in mortar that could be harmful to mortar properties.